Automotive accessory drive belt tensioners are commonly used for maintaining proper tightness of flexible members which power such accessories as a water pump, air conditioning compressor, alternator, and power steering pump. Although many types of tensioners are used, the spring loaded variety is most common.
U.S. Pat. No. 4,832,665 to Kadota et al. discloses a spring type tensioner in which the power spring is immobilized prior to engagement of the tensioner with an engine by means of a pin, 27, which may be extracted after the tensioner is bolted to the engine. A possible problem could occur with the device shown in the '665 patent after pin 27 is extracted. If the tensioner is removed from the engine without reinsertion of pin 27, such as would likely be the case after an engine equipped with the tensioner has been in use for some time, the spring could be allowed to unwind violently. A tensioner arm assembly according to the present invention obviates this problem by controlling the location of the outer and inner ends of the spring not only before the tensioner arm assembly is installed in the engine, but also during and after removal of the arm assembly from an engine.